Kerosene is widely used for heating purposes and cooking purposes. When conventional kerosene is used for heating purposes there is an oily smell when the kerosene is being handled when supplying the oil, for example, and the user is subjected to an unpleasant sensation. Furthermore, incomplete combustion occurs on ignition and on extinguishing when this type of kerosene is used in an open-type stove such as a portable stove or a fan heater or when it is used in a small portable cooking stove in the kitchen, and there is a problem in that there is an unpleasant smell due to the unburned hydrocarbons which are produced at this time.
On the other hand, the demand for higher levels of safety and comfort (the production of smaller amounts of NOx, hydrocarbon compounds, CO, SO2, etc. and no accompanying unpleasant smell) by the user in connection with oil stoves has increased year by year. Furthermore, in recent years kerosene which has been stored through the summer has been recirculated and problems also arise in that oil stoves break down as a result of using such kerosene. There is thus also a demand for improvement of the storage stability of kerosene. In view of such a situation, the kerosene which is being used in oil stoves must respond satisfactorily to these user demands.
A method in which a kerosene vaporization catalyst is used, described in JP-B-59-16814, a method in which a deodorising agent is added to the kerosene, described in JP-B-54-32003, and a kerosene comprising n-paraffins and iso-paraffins, described in JP-A-63-150380, for example, have been suggested as methods for overcoming the generally observed problems of the unpleasant sensation when handling kerosene and the unpleasant smell when kerosene is being ignited or extinguished.
However, with the method in which a kerosene vaporization catalyst is used, the catalyst deteriorates with the passage of time and so it has been difficult to maintain clean combustion over a prolonged period of time. Furthermore, the method in which a deodorizing agent is added to kerosene is not very effective because of the problem that the smell is not agreeable to some people. Furthermore, although kerosenes containing n-paraffins and iso-paraffins do not have an unpleasant smell when they are being handled, when they are ignited or when they are extinguished, and the exhaust gas is also clean, the production costs are greatly increased and there is a problem in that kerosene of this type is inevitably expensive. Furthermore, kerosenes containing iso-paraffins and n-paraffins which have 9 or 10 carbon atoms as the main component have a lower density than existing kerosenes and the fuel consumption by volume is increased, and so, for example, there is a risk that the JIS specification (of the Japanese Standards Association) for the indicated fuel consumption of an oil stove will not be satisfied. Moreover, the flash point is reduced and there are problems with safety in respect, for example, of the extinguishing time.